UPDATED April 17 at 1:20 p.m. EDT

COLORADO SPRINGS, Colo. — After a one-day delay due to weather, a SpaceX Falcon 9 rocket successfully launched a Dragon cargo spacecraft on a mission to deliver cargo to the International Space Station, but the rocket’s first stage failed to survive a hard landing on a ship.

The Falcon 9 lifted off from Cape Canaveral Air Force Station, Florida, at 4:10 p.m. local time. Weather, which postponed a launch attempt the previous day, was not a factor for the launch, and the Falcon’s second stage delivered the Dragon spacecraft into orbit 10 minutes after liftoff.

The Dragon spacecraft is carrying 2,015 kilograms of cargo for the ISS, including experiments, crew supplies and other equipment, on SpaceX’s sixth mission under its Commercial Resupply Services contract with NASA. Dragon will later return about 1,370 kilograms of science investigations and other items.

Much of the attention about the launch was focused, though, on SpaceX’s plans to attempt to land the first stage on the company’s “autonomous spaceport drone ship” in the Atlantic Ocean, part of the company’s efforts to make the first stage reusable.

That effort was only partially successful. “Rocket landed on droneship, but too hard for survival,” SpaceX Chief Executive Elon Musk tweeted about 20 minutes after launch.
He later said that “excess lateral velocity” caused the booster to tip over after landing on the ship. Video released by SpaceX showed the stage toppling over and exploding several seconds after landing.

In a tweet he posted late April 14, but later deleted, Musk said that friction in a throttle valve in one engine created a “control system phase lag” that resulted in the horizontal motion. “Should be easy to fix,” he said.

“I’m pretty sure we’ll figure this out and make it work,” SpaceX Vice President Hans Koenigsmann said at a post-launch press conference at NASA’s Kennedy Space Center in Cape Canaveral, Florida. “It’s just a matter of finding the right parameters, finding the right method to do this. I don’t think there’s something fundamental” that needs to be changed.

This landing attempt was the second time the company tried to land a Falcon 9 first stage on its ship. SpaceX attempted a landing during a January launch of another Dragon spacecraft, crashing the stage on the deck of the ship.

Hawthorne, California-based SpaceX planned to attempt a first-stage landing following the February launch of the Deep Space Climate Observatory spacecraft, but rough seas forced SpaceX to withdraw the ship. SpaceX later said the stage touched down on the ocean at the planned target site.

“If the drone ship would have been there, it would have been a good landing,” Koenigsmann said at an April 12 prelaunch press conference at KSC in Cape Canaveral, Florida.

Dragon arrived at the ISS April 17 at 6:55 a.m. Eastern time. It will remain at the station for about five weeks before returning to Earth.

SpaceX’s drone ship, which is intended as a landing pad for the Falcon 9 first stage. Credit: SpaceX
SpaceX’s drone ship, which is intended as a landing pad for the Falcon 9 first stage. Credit: SpaceX

It was not immediately clear whether SpaceX’s second failure to recover the Falcon 9 first stage from its drone ship will affect the company’s timetable for landing the hardware on a ground-based pad.

SpaceX President and Chief Operating Officer Gwynne Shotwell said during an interview just before the April 14 launch that the first attempt to put the Falcon 9 booster down on a land-based platform could come as early as this summer.

Earlier this year, SpaceX and the Air Force announced plans for the company to convert unused launch pads at Vandenberg Air Force Base in California and Cape Canaveral Air Force Station into landing pads.

SpaceX recently began construction on the Cape Canaveral landing pad, and environmental work is underway for the landing pad at Vandenberg, Shotwell said in the interview, conducted here at the 31st Space Symposium.

The first attempt to stick a Falcon 9 booster on a landing pad at Vandenberg could come as early as July following the launch of the French-U.S. Jason-3 ocean altimetry satellite mission, she said.
“We’d love to land Jason-3, which we’re going to launch in July; we’d love to land that on land at Vandenberg,” Shotwell said.
Another possibility “might” be following the scheduled June launch of a commercial resupply mission to the International Space Station from the Cape, Shotwell said.

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...

Mike Gruss covers military space issues, including the U.S. Air Force and Missile Defense Agency, for SpaceNews. He is a graduate of Miami University in Oxford, Ohio.